DESCRIPTION: This research program has two overall goals. The first study will identify early characteristics of children with autism and their environments that predict their developmental course. Specifically, the investigators will compare the differential effectiveness of experimental interventions in three domains of non-verbal communication: 1) sharing attention or interests, 2) requesting objects or assistance, and 3) sharing emotions. The second study continues the longitudinal follow-up of a sample of 48 young adults with autism. This study has a twofold objective. First, the investigators will determine whether the transition to adulthood affects symptoms, behavior problems, adaptive behaviors, as well as language and mental skills. Secondly, the study is to identify correlates and predictors of the perceived quality of life of adults with autism and their parents as well as the families? capacities to sustain meaningful routines.